A report on Tystie's sail, after about three and a half thousand miles of coastal and ocean sailing:
I'm content now that this is a suitable sail-plan for ocean passages. I've used all the reefs, down to one panel and then bare poles in 40 knots. I never felt that the sail shape was a big mistake, and ought to be scrapped :-) The clew might be a little higher. I was dragging it through the bigger wave-tops occasionally. Partly, I made the sail too big (too greedy, as usual), but partly, it would be better with more forward rake to the mast, as Fantail has. David Thatcher was hoping to be able to rake Footprints' mast forward this winter.
The sail has much more drive if I keep the yard as vertical as possible as I reef (because of the fan-induced camber), but once I get down to four or five reefs, I mustn't tighten up the yard hauling parrel, but let the yard go down to a lesser angle (which noticeably de-powers the sail). If I keep the yard peaked up, there is a high risk of getting the top of it the wrong side of the topping lifts. This can be corrected, by letting out the sheet, lowering the sail and hoisting it again, but it's better if I avoid having to do so. I've ended up by watching the peak of the yard as I reef, and making sure that there is enough slack in the yard hauling parrel to keep it aft of the topping lifts. I should really change the topping lifts so that the standing part is further forward, if I can figure out how.
I really do have to pull the port side mast lift well aft, to avoid getting the forward ends of battens and yard the wrong side of it when I'm on port tack, I have four reefs or more, and the sail is very twisted. Both mast lifts should come down to a point about 1.5m aft of the tack. I'm having to use a span to haul the lift back to this point, which is not ideal, and the cloth triangle to which the lift is attached should really be moved aft.
The top three batten pockets all chafed in way of the mast. I think this is because at each one, the upper panel has less camber than the lower panel, and the pocket tends to rotate about the batten to equalise the forces acting on it. This results in the fender being too low. This is a downside of using Arne's simpler sail construction. Footprints' sail may not suffer in this way, because the pockets were attached at two points on the sail. The lower batten pockets, where there is equal camber in the panels, are OK so far.
I wouldn't want more than the 6% camber we put in, for ocean passages. Premium windward ability is simply not at the top of the priority list. When the wind falls light, but there are still wind waves along with one or more swells from different directions, the sail panels empty and fill again with a big bang. This may be just the same as happens with a bermudan sail, but we junkies shouldn't have to put up with it. I have now formulated:
"Tyler's Hypothesis - the amount of camber to be added to junk rig sail panels is inversely proportional to the distance offshore that it is intended to sail".
I think that 4% is the sensible limit, 6% is the not-so-sensible limit for offshore boats, and any more is strictly for inshore boats. If I made this sail again, I would start to decrease the camber sooner, that is, three panels at 6%, then decreasing towards the head, rather than four panels at 6%.
My double sheeting, upper and lower, is still working out well. I spent such a lot of time on the passage from Opua to Tubuai with three reefs or more that I'm glad I had it. With four reefs or more, I could wish that the sheeting extended further up, to the next batten, but with three reefs or less, the twist is OK.
I've changed the luff/throat hauling parrel so that it now starts at the batten 2 from the top, goes around the mast to a block on the yard, back around the mast to batten 3 from the top, around the mast to batten 4 from the top, and to the deck. I no longer have a second luff hauling parrel. I don't get the sail perfectly crease-free 100% of the time, but I get it good enough for me to look at without distressing myself.
I'm glad I went for the carbon spars, despite the cost, time and hassle it took to make them - I didn't have any fears about broken spars on this passage, and the battens are very stiff now that they are fully cured.